I should write the following sentence as a predicate logic formula:
"It is not true that all soccer players are fearless and it is not true that some sailors aren't fearless."
I would write it like this, but I'm not sure if it is correct: $\neg(\forall x)F(x)\land\neg (\exists y)\neg F(y)$ .
Especially I'm not sure about those variables and quantifiers since once we are talking about ALL soccer players and second we are talking about SOME sailors - in other words, two different object are quantified.